This invention relates to data processing apparatus of the kind comprising an array of processing elements operable in parallel on data held in respective local memories, the elements being connected together in rows and columns to allow transfer of data between adjacent elements in each row and column.
Such apparatus is described for example in British Patent Specifications Nos. 1 445 714 and 2 103 400, and is particularly useful for processing data comprising large arrays or vectors, consisting of a large number of individual data items.
In operation of such apparatus, it is necessary to map the data on to the processing elements in some way, i.e. to assign each data item to the particular processing element that is to operate upon it. Also, it may be necessary to change the mapping of the data during the course of a calculation. The mapping of data items and the transformation between different mappings are discussed in a paper by P. M. Flanders, entitled "A unified approach to a class of data movements on an array processor", IEEE Transactions on Computers, Vol. C-31, no. 9, September 1982.
The object of the present invention is to provide a data processing apparatus of the kind specified, in which transformation between different data mappings is facilitated.